Appreciate the advice/information. My "test drive matrix" I think will be limited by very low dealer inventory for 550 and difficulty getting straight answer from sales guy on what options are really on cars.
Low inventory brings up question about how long I will need to wait for something very close to what I want---are there regional inventories dealers can draw from and/or dealer swaps or will I need to wait for a car to get built in Germany? Hopefully I will get better feel after driving but now leaning towards 550 xi with just cold weather package. If standard suspension wheel/tire combo is too floaty, my understanding is M Sport for 550 xi does not change suspension (just wheel/tire and appearance) so my only option for more sporty handling would be Dynamic Handling Package?